Device for treating eye tissue using laser pulses

ABSTRACT

An ophthalmic device for treating eye tissue using laser pulses comprises a projection optical unit for focused projection of the laser pulses and a scanning device, with a movable mirror, arranged downstream from the projection optical unit, for deflecting the laser pulses projected by the projection optical unit in at least one deflection direction. The ophthalmic device moreover comprises an optical correction element arranged downstream of the scanning device, which correction element is configured to image, in a focused manner, the laser pulses deflected by the scanning device on an intended treatment area in the eye tissue. The optical correction element renders it possible to therefore correct image field curvatures caused by the scanning device arranged downstream from the projection optical unit and, for example, image the deflected laser pulses in focus onto a plane.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S.application Ser. No. 14/264,198, filed Apr. 29, 2014, which claimsbenefit of European Application No. 13002266.8, filed Apr. 29, 2013, thedisclosures of which are each incorporated herein by reference in itsentirety.

TECHNICAL FIELD

The present disclosure relates to an ophthalmic device for treating eyetissue using laser pulses. In particular, the present disclosure relatesto an ophthalmic device for treating eye tissue using laser pulses,comprising a projection optical unit for focused projection of the laserpulses into the eye tissue and a scanning device arranged downstreamfrom the projection optical unit, for deflecting the laser pulsesprojected by the projection optical unit in at least one deflectiondirection.

BACKGROUND

Ophthalmic devices for treating eye tissue using laser pulses, in whichthe scanning device is arranged downstream from the projection opticalunit, are advantageous in that they have a simple focusing optical unit.However, a disadvantage thereof is that, as a result of the downstreamconnection of the scanning device, there is an image field curvature,i.e. a curved treatment surface. In order to compensate for this imagefield curvature, the focus of the laser pulses deflected by the scanningdevice needs to be corrected.

US 2011/245814 describes a device with a downstream scanning device witha single mirror suspended by means of a universal joint, which enablesshort work distances and strong focusing, as are of interest in e.g.ophthalmology for lens surgery. However, a disadvantage of thisarrangement lies in the restricted dynamic response as a result ofco-rotating drives. Moreover, the mirror surface in accordance with US2011/245814 does not lie in the center of the rotation, leading to anadditional distortion of the image field curvature because the mirror isdisplaced along the optical axis during scanning.

SUMMARY

Aspects of the present disclosure propose an ophthalmic device fortreating eye tissue using laser pulses, which has a projection opticalunit with a downstream scanning device and does not have at least someof the disadvantages of the known systems.

According to aspects of the present disclosure, these are achieved bythe features of the independent claims. Moreover, further examplesemerge from the dependent claims and the description.

The ophthalmic device for treating eye tissue using laser pulsescomprises a projection optical unit for focused projection of the laserpulses and a scanning device, with a movable mirror, arranged downstreamfrom the projection optical unit, for deflecting the laser pulses by theprojection optical unit in at least one deflection direction.

In particular, the present disclosure describes the ophthalmic devicemoreover comprising an optical correction element arranged downstream ofthe scanning device, which correction element is configured to image, ina focused manner, the laser pulses deflected by the scanning device onan intended treatment area in the eye tissue.

In some examples, the optical correction element is configured to image,in a focused manner, the laser pulses deflected by the scanning deviceon a plane for correcting image field curvatures caused by the scanningdevice.

In some examples, the scanning device is configured to move the mirrorabout a pivot point lying on the optical axis of the projection opticalunit and on the mirror surface.

In some examples, the scanning device comprises a plurality of lineardrives coupled to the mirror and the ophthalmic device comprises acontrol module configured to control the linear drives in such a waythat the linear drives rotate the mirror about a pivot point lying onthe optical axis of the projection optical unit and on the mirrorsurface.

In some examples, the optical correction element is an example as a lenselement.

In some examples, the lens element has a lens surface equidistant to thepivot point of the mirror.

In some examples, the scanning device is configured to move the mirrorabout a pivot point lying away from the optical axis of the projectionoptical unit and the optical correction element is embodied as ananamorphic optical element.

In some examples, the ophthalmic device comprises a patient interfacedevice which can be fastened to the eye of the patient and which isrotatably mounted about the pivot point of the mirror.

In some examples, the ophthalmic device comprises a zoom system foradjusting a depth of focus in the projection direction, and a patientinterface device which can be fastened to the eye of the patient andwhich is rotatably mounted about the optical axis of the zoom system.

In some examples, the optical correction element is securely ordetachably connected to the patient interface device.

In some examples, the scanning device is embodied such that it can bemoved out of the beam path between scanning device and eye in the stateof the patient interface device in which it is fastened to the eye.

In some examples, the patient interface device has a cavity provided forholding liquid, and an opening, which opening is closed by the eye inthe state of the patient interface device in which it is fastened to theeye.

In some examples, the projection optical unit has a diameter, whichsubstantially corresponds to the largest extent of the mirror surface ofthe mirror.

In some examples, the optical correction element is embodied as lenselement configured to image, in a focused manner, the laser pulsesdeflected by the scanning device on an intended treatment area away fromthe focal length of the projection optical unit.

In some examples, the ophthalmic device comprises a divergence modulatorwhich is arranged upstream of the projection optical unit and configuredto shift the divergence of the laser beam, depending on the deflectionof the laser pulses, in such a way that image field curvatures caused bythe scanning device are at least partly compensated.

In some examples, the divergence modulator comprises two optical lensesarranged in series, wherein at least one of the lenses is coupled to amovement driver in a manner displaceable on an optical axis formodulating the divergence of the laser beam; a deformable lens; adeformable mirror element; a spatial light modulator for modulating thewavefront of the laser beam; an area light modulator for modulating thereflection angles at a plurality of points of a reflection surface; arefraction modulator for modulating the refractive index of an opticalelement at a plurality of points in the cross section of the beam path;and/or an amplitude modulator for modulating the amplitude at aplurality of points in the cross section of the beam path of the laserbeam.

In some examples, the ophthalmic device comprises a detection moduleconfigured to detect the optical correction element and control asetting of the scanning device depending on a detection of the opticalcorrection element.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following text, examples of the present disclosure are describedon the basis of examples. The exemplary examples are illustrated by thefollowing attached figures:

FIG. 1 schematically shows a cross section of an ophthalmic device fortreating eye tissue using laser pulses, comprising a scanning devicearranged downstream from the projection optical unit in accordance withone or more aspects of the present disclosure.

FIG. 2 schematically shows a cross section of an ophthalmic device fortreating eye tissue using laser pulses, comprising a scanning devicearranged downstream from the projection optical unit and an opticalcorrection element arranged downstream from the scanning device inaccordance with one or more aspects of the present disclosure.

FIG. 3 schematically shows a cross section of an ophthalmic device fortreating eye tissue using laser pulses, comprising a scanning devicearranged downstream from the projection optical unit and an opticalcorrection element arranged downstream from the scanning device andintegrated into a patient interface in accordance with one or moreaspects of the present disclosure.

FIG. 4 schematically shows a cross section of an ophthalmic device fortreating eye tissue using laser pulses, comprising a scanning devicearranged downstream from the projection optical unit and a drive systemfor moving the scanning device in accordance with one or more aspects ofthe present disclosure.

FIG. 5 schematically shows a cross section of an ophthalmic device fortreating eye tissue using laser pulses, comprising a scanning devicearranged downstream from the projection optical unit and a drive systemfor parallel displacement of a mirror of the scanning device, whichmirror can be rotated around a pivot point arranged at a distance fromthe optical axis of the projection optical unit in accordance with oneor more aspects of the present disclosure.

FIG. 6 schematically shows a cross section of an ophthalmic device fortreating eye tissue using laser pulses, comprising a scanning devicearranged downstream from the projection optical unit and a drive systemfor parallel displacement of a mirror of the scanning device, whichmirror can be rotated around a pivot point arranged on the optical axisof the projection optical unit in accordance with one or more aspects ofthe present disclosure.

FIG. 7 schematically illustrates the deflection of a laser pulse onto atarget point in the eye tissue by rotating the mirror of the scanningdevice arranged downstream from the projection optical unit inaccordance with one or more aspects of the present disclosure.

FIG. 8 schematically illustrates the scanning of target points on atreatment surface in the eye tissue by parallel displacement androtation of the mirror of the scanning device arranged downstream fromthe projection optical unit in accordance with one or more aspects ofthe present disclosure.

FIG. 9 schematically shows a cross section of an ophthalmic device fortreating eye tissue using laser pulses, comprising a scanning devicearranged downstream from the projection optical unit and a correctionsystem for a change in focal length depending on the deflection of thelaser pulses in accordance with one or more aspects of the presentdisclosure.

FIG. 10 schematically shows a cross section of an ophthalmic device fortreating eye tissue using laser pulses, comprising a scanning devicearranged downstream from the projection optical unit and a zoom systemfor a change in focal length depending on the deflection of the laserpulses in accordance with one or more aspects of the present disclosure.

DETAILED DESCRIPTION

In FIGS. 1-10, reference sign 1 in each case relates to an ophthalmicdevice for treating eye tissue 6 using laser pulses.

The ophthalmic device 1 comprises a laser source 10 for producing thelaser pulses, preferably femtosecond laser pulses, for treating eyetissue 6, and a projection optical unit 12 for the focused projection ofthe laser pulses. The laser pulses are supplied to the projectionoptical unit 12 from the laser source 10 by means of an opticaltransmission system 11.

As depicted schematically in FIGS. 1-10, the ophthalmic device 1comprises a scanning device 2 arranged downstream from the projectionoptical unit 12. The scanning device 2 comprises at least one movablemirror 20 for deflecting the laser pulses projected by the projectionoptical unit 12 in at least one deflection direction by rotating d themirror 20 around at least one axis of rotation. The scanning device 2 ispreferably configured to move the mirror 20 around a plurality of axesof rotation which extend through a pivot point A lying on the opticalaxis v of the projection optical unit 12. As will be described later,the pivot point A is displaceable on the optical axis v. In otherexamples, the mirror 20 is rotatable around one or more axes of rotationwhich extend through a pivot point B lying outside of the optical axisv.

As depicted schematically in FIGS. 2, 3, 5, 6, the scanning device 2comprises a drive system with a plurality of linear drives 21, 22coupled to the mirror 20. By way of example, the drives are embodied aspiezoelectric or electromagnetic drives. The ophthalmic device comprisesa control module 23 configured to control the linear drives 21, 22 insuch a way that these rotate the mirror 20 around a pivot point A, whichpreferably lies on the optical axis v of the projection optical unit 12and on the mirroring surface of the mirror 20 (mirror surface), bytranslational movements u, w in correspondingly opposite directions.There being more than two linear drives 21, 22 enables rotations daround different axes extending through the pivot point A in thexyz-space.

As illustrated in FIG. 1, the rotation d of the mirror 20 of thedownstream scanning device 2 causes curvature of the image field or anintended treatment surface s. In other words, the focus F of the laserbeam L focused by the projection optical unit 12 moves on a circular arcs′ in the case of a rotation d of the mirror 20 around an axis ofrotation extending perpendicular to the plane of the drawing, or itmoves on a spherical shell, as indicated in FIG. 1 by the deflectedlaser beams L′, L″, in the case of a rotation d of the mirror around aplurality of axes of rotation extending through a pivot point A lying onthe optical axis v, wherein the circular arc s′ or the spherical shellcorresponds to the curved or distorted image field. A rotation around apivot point B arranged outside of the optical axis v causes anadditional distortion of the image field curvature, as is depicted, forexample, in FIG. 5 by the circular arc s″, since the mirror 20 ismoreover displaced along the optical axis v by the rotational movement.

In the examples illustrated in FIGS. 2 and 3, the ophthalmic device 1comprises an optical correction element 4 arranged downstream from thescanning device 2, which correction element is configured to image thelaser pulses deflected by the scanning device 2 in focus onto anintended treatment surface s in the eye tissue 6, for example onto anintended treatment plane for producing a planar cut, as indicated inFIG. 2 by the corrected laser beams L*, L**. In one variant, thecorrection element 4 is embodied as an optical lens element. By way ofexample, the lens element has a lens surface equidistant from the pivotpoint A of the mirror 20, as indicated in FIG. 2 by the radius r.

In order to increase the distance between the scanning device 2 and theeye of the patient, the optical correction element 4 is embodied as alens element in some examples, which lens element is configured in sucha way that the laser pulses deflected by the scanning device 2 areimaged in focus onto an intended treatment surface lying outside of thefocal length f of the projection optical unit 12. That is to say, thelens element of the optical correction element 4 causes a defineddisplacement or enlargement of the focal length f of the projectionoptical unit 12. In a further example, the correction element 4 isadditionally configured to increase the refractive power and thereforefocus the laser beam more, i.e., project the laser beam onto a focuswith a reduced spot size. The projection optical unit 12 and the opticalcorrection element 4 are matched to one another in a targeted manner inone variant, in order, as a combined projection optical unit, to achievea defined spot quality of the projected laser pulse or laser beam, forexample in respect of size and shape (diameter across the projectiondirection, length in the projection direction).

For configurations and/or applications in which the mirror 20 is rotatedaround a pivot point B lying outside of the optical axis v of theprojection optical unit 12, use is made of a correction element 4embodied as an anamorphic element since, when the deflection mirror ofthe scanning device 2 rotates around a pivot point B lying outside ofthe optical axis v of the projection optical unit 12, furtherdistortions of the image field emerge, which distortions arecharacterized by asymmetry in respect of the projection axis (see e.g.circular arc s″ around pivot point B in FIG. 5).

In other examples, the optical correction element 4 is securely orinterchangeably connected to the ophthalmic device 1 or a patientinterface device 5 of the ophthalmic device 1. Therefore, it is possibleto insert different correction elements 4 into the patient interfacedevice 5 in an interchangeable manner and use these for the treatment ofthe eye tissue 6.

As illustrated schematically in FIG. 3, the patient interface device 5comprises, for example, a vacuum applicator 51, e.g. a suction ring, tobe fastened to the eye 60 of the patient. In some examples, the patientinterface device 5 comprises a contact body 52, e.g. an applanationbody, for establishing contact on the cornea of the eye 60, or a cavitythat can be filled with liquid, which cavity has an opening which issealed by the eye 60 or the cornea in the state where the patientinterface device 5 is applied to the eye 60. In some examples, theoptical correction element 4 is configured as a contact body, either asan applanation body with a flat contact surface or as a contact bodywith a curved contact surface, depending on the variant and/orapplication. In some examples, the optical correction element 4 and aseparate applanation body form an optical correction system configuredto image the laser pulses deflected by the scanning device 2 in focusonto the intended treatment surface s in the eye tissue 6.

The patient interface device 5 is connected to the ophthalmic device 1in some examples. For an ergonomic improvement of the applicability onthe eye 60, the patient interface device 5 is rotatably mounted, forexample around two axes of rotation. In some examples, the patientinterface device 5 is rotatably mounted around the pivot point A of themirror 20, i.e. the axes of rotation of the rotary joints of the patientinterface device 5 extend through the pivot point A of the mirror 20. Byway of example, one of the axes of rotation of the rotary joints of thepatient interface device 5 corresponds to the optical axis v of theprojection optical unit 12 or of a zoom system 83, described below, suchthat the patient interface device 5 is rotatable around the optical axisv (and, if the pivot point A of the mirror 20 lies on the optical axisv, also around this pivot point A).

In some examples, the scanning device 2 is embodied and connected to theophthalmic device 1 in such a way that it can be moved out of the beampath by means of a repositioning device, for example by means of arotation around a rotary joint or by means of a translation, such thatit is possible to see into the eye 60. To this end, the repositioningdevice comprises a pivot bearing attached to the ophthalmic device 1 ora guide, by means of which pivot bearing or guide the scanning device 2can be moved out of the beam path and can be coupled back into the beampath, either manually or by means of a drive system, such that, in thestate where the scanning device 2 is coupled into the beam path, thelaser pulses supplied by the projection optical unit 12 can again bedeflected precisely onto target points F by the mirror 20 of thescanning device 2. It should be noted here that in the state in whichthe scanning device 2 is moved out of the beam path, an unhindered viewof the eye 60 is possible, both in the state where the patient interfacedevice 5 is fastened to the eye 60 and when the patient interface device5 is not attached to the eye 60 or does not contact the eye 60, but ismerely arranged over the eye 60.

In some examples, the ophthalmic device 1 comprises a detection module 9configured to detect the optical correction element 4 and comprising acontrol module configured to control the setting of the scanning device2 in respect of the position or the rotational angle of the mirror 20depending on a detection of the optical correction element 4. Thedetection of the optical correction element 4 includes the position ofthe correction element 4 in respect of the ophthalmic device 1 or thescanning device 2, the type of correction element 4, optical propertiesof the correction element 4, which are e.g. assigned to the type ofcorrection element 4, and/or dimensions of the correction element 4, inparticular the thickness of the correction element 4. Depending theexample and the parameters to be detected, the detection module 9comprises one or more optical sensors, distance sensors, electricalsensors, electromechanical sensors and/or electromagnetic sensors, e.g.,RFID sensors, for detecting the optical correction element 4. Inparticular, the control module of the detection module 9 is configuredto control the scanning device 2 depending on the detected position ofthe correction element 4 and thereby dynamically adapt the position orthe rotational angle of the mirror 20 to positional changes of thecorrection element 4 or of the patient in order to deflect the laserpulses to defined target points F in the eye tissue 6 depending on theposition or positional changes. Moreover, the control module of thedetection module 9 is configured to align the pivot point A of themirror 20 with respect to the patient interface device 5 and tocompensate the tile of the patient interface device 5 caused by rotaryjoints of the patient interface device 5.

In the examples depicted in FIGS. 4, 5, and 6, the ophthalmic device 1has a drive system 200 configured to displace the mirror 20 in parallel.In particular, the drive system 200 is configured to displace the mirror20 with a translational movement component t−, t+ along the optical axisv. As a result of the parallel displacement of the mirror 20 of thescanning device 2 arranged downstream from the projection optical unit12, the distance between the mirror surface and the projection opticalunit 12 is modified, causing a shift in the focus in the projectiondirection in the case of an unchanged focal length f of the projectionoptical unit 12. Reducing the distance between the mirror surface andthe projection optical unit 12 causes an increase in the distancebetween the focus and the mirror surface, and therefore enables afocused projection of the laser pulses onto lower lying points F in theeye tissue 6 (displacement in projection direction or z-direction);increasing the distance between the mirror surface and the projectionoptical unit 12 by contrast causes a reduction in the distance betweenthe focus and the mirror surface, and therefore enables a focusedprojection of the laser pulses onto higher lying target points F in theeye tissue 6 (displacement counter to the projection direction orz-direction).

In the example according to FIG. 4, the direct system 200 for paralleldisplacement of the mirror 20 comprises a drive 24 coupled to thescanning device 2, which drive is configured to displace the scanningdevice 2 along the optical axis v of the projection optical unit 12 oracross the optical axis v of the projection optical unit 12.

In the examples in FIGS. 5 and 6, the drive system 200 comprises atleast one drive 21, 22 coupled to the mirror 20, which drive isconfigured to displace the mirror 20 in parallel. By way of example, thedrive system 200 comprises a plurality of linear drives 21, 22 coupledto the mirror 20, which drives are configured to displace the mirror 20in parallel.

As depicted schematically in FIGS. 5 and 6, the linear drives 21, 22 aremoreover configured to rotate the mirror 20 around at least one pivotpoint A, B by means of correspondingly opposing translational movementsu, w. In the illustration of FIG. 5, the rotation d is performed arounda pivot point B lying outside of the optical axis v of the projectionoptical unit 12. In the illustration of FIG. 6, the rotation d isperformed around a pivot point A lying on the optical axis v of theprojection optical unit 12 and on the mirror surface of the mirror 20.There being more than two linear drives 21, 22 enables rotations daround different axes extending through the pivot point A, B in thexyz-space. Therefore, the drive system 200 allows the mirror 20 and thepivot point A, B thereof to be displaced along the optical axis v of theprojection optical unit 12 and the mirror 20 to be rotated around thepivot point A, B in order to treat the eye tissue 6 by means of laserpulses deflected in focus onto target points F.

FIG. 7 schematically illustrates the focal length f of the projectionoptical unit 12 on the optical axis v and the circular arc e definedthereby, on which the deflected laser beam L can be deflected in focusin the case of a rotation d of the mirror 20 around an axis of rotationextending through the pivot point A normally to the plane of thedrawing, or the spherical shell defined by the focal length, on whichspherical shell the deflected laser beam L can be deflected in focus inthe case of rotations d of the mirror 20 around a plurality of axes ofrotation extending through the pivot point A.

FIG. 8 schematically illustrates the combination of a rotation d of themirror 20 around the pivot point A, lying on the optical axis v and onthe mirror surface, with a movement of the mirror 20 or of the pivotpoint A with a translational movement component t−, t+ along the opticalaxis v. FIG. 8 illustrates the combination of rotation d anddisplacement of the mirror 20 using the example of treating targetpoints Fα, F, Fβ lying on a treatment line c in the eye tissue 6. Asshown in FIG. 8, the control module 23 controls the drive system 200 orthe linear drives 21, 22 in such a way that, for treating the targetpoints Fα, F, Fβ, the drive system 200 displaces the pivot point or themirror 20 to a point A−, A, A+ on the optical axis v of the projectionoptical unit 12, which point has a defined distance d−, d, d+ withrespect to the focal length f of the projection optical unit 12. Thepivot point A−, A, A+ therefore lies on a point of intersection betweenthe mirror surface and the optical axis v, wherein the distance d−, d,d+ from the pivot point A−, A, A+ or from the point of intersection withrespect to the focal length f of the projection optical unit 12corresponds to the distance between the relevant target point Fα, F, Fβand the pivot point A−, A, A+ or point of intersection. The focal lengthf of the projection optical unit 12 and the relevant target point Fα, F,Fβ therefore each lie on a common circular arc e or on a commonspherical shell around the pivot point A−, A, A+ or point ofintersection on the optical axis v. Here, the mirror 20 is rotatedaround the pivot point A−, A, A+ in such a way that the deflected mirror20α, 20, 20β deflects the laser beam Lα, L, Lβ in the direction of thetarget point Fα, F, Fβ. Hence the laser beam Lα, L, Lβ or the laserpulses is/are projected in focus onto the relevant target point Fα, F,Fβ on the treatment line c by the projection optical unit 12 by means ofthe deflected mirror 20α, 20, 20β. It should be noted here that thecombination of rotation d and displacement should not be performedsequentially but preferably in parallel/simultaneously such that thetarget points Fα, F, Fβ can be put into focus and treated as quickly aspossible.

In one variant, the control module 23 is configured to control the drivesystem 200 and the scanning device 2 in such a way that the laser pulsesare deflected in focus and projected onto target points Fα, F, Fβ of athree-dimensional treatment surface s in the eye tissue 6.Three-dimensional treatment or volume treatment is achieved thereby.

In the following paragraphs and with reference to FIGS. 9 and 10, someexamples of the ophthalmic device 1 with a correction system aredescribed, which correction system is configured to undertake a changein focal length depending on the deflection of the laser pulses by meansof one or more optical elements arranged upstream from the projectionoptical unit 12 or integrated into the projection optical unit 12.

FIG. 9 illustrates an example in which the ophthalmic device 1 has adivergence modulator 81, arranged upstream from the projection opticalunit 12, as a further feature in the optical transmission system 11. Thedivergence modulator 81 is configured to shift the divergence of thelaser beam depending on the deflection of the laser pulses in such a waythat image field curvatures caused by the scanning device 2 arecompensated for, at least in part. Depending on the example, thedivergence modulator 81, for divergence modulation, comprises twooptical lenses arranged in series, wherein at least one of the lenses iscoupled to a movement driver in a manner displaceable on the opticalaxis v for modulating the divergence of the laser beam; a deformablelens; a deformable mirror element; a spatial light modulator formodulating the wavefront of the laser beam; an area light modulator formodulating the reflection angles at a plurality of points of areflection surface; a refraction modulator for modulating the refractiveindex of an optical element at a plurality of points in the crosssection of the beam path; and/or an amplitude modulator for modulatingthe amplitude at a plurality of points in the cross section of the beampath of the laser beam. The divergence modulator 81 is controlled by acontrol module 80 depending on the deflection of the laser pulsesperformed by the scanning device 2, i.e. depending on one moredeflection angles of one or more mirrors 20 of the scanning device 2. Tothis end, the control module 80 uses correction parameters or controlvalues for controlling the divergence modulator 81, which correctionparameters or control values are stored in a manner assigned to variousdeflection angles and cause a corresponding divergence modulation forcompensating image field curvatures at the respectively relevantdeflection angle, as indicated in FIG. 9 by the corrected laser beamsL*, L**.

FIG. 10 illustrates an example, in which the ophthalmic device 1 has azoom system 83, arranged upstream from the projection optical unit 12 orintegrated into the projection optical unit 12, as a further feature inthe optical transmission system 11. The zoom system 83 is configured toundertake a change in focal length depending on the deflection of thelaser pulses in order to compensate, at last in part, image fieldcurvatures caused by the scanning device 2. The zoom system 83 ismoreover configured to set the spot size and/or aberrations. The zoomsystem 83 comprises at least two optical systems that can be setindividually, for example two lens groups, each with one or more movablelenses, and/or one or more deformable mirrors/lenses and correctionelements that can be inserted. The optical systems are coupled to adrive system comprising one or more electric motors and configured toset the optical systems individually, for example, by displacing lensesalong the optical axis v and/or normally to the optical axis v (into/outof the beam path). The zoom system 83 is controlled by a control module82, depending on the deflection of the laser pulses performed by thescanning device 2, i.e. depending on one or more deflection angles ofone or more mirrors 20 of the scanning device 2. To this end, thecontrol module 82 uses correction parameters or control values forcontrolling the zoom system 83, which correction parameters or controlvalues are stored in a manner assigned to various deflection angles andcause a corresponding change in focal length for compensating imagefield curvatures at the respectively relevant deflection angle, asindicated in FIG. 10 by the corrected laser beams L*, L**.

In different examples, the projection optical unit 12 is embodied as azoom system 83 or the zoom system 83 is used as a projection opticalunit 12. In some examples, the whole projection optical unit 12 isdisplaced depending on the deflection of the laser pulses so as to causea compensating focus shift. In some examples, provision is made for adivergence modulator 81 and a zoom system 83, which are actuated in sucha way that they undertake a shift in focus, depending on the deflectionof the laser pulses, by a combination of a divergence modulation of thelaser beam by means of the divergence modulator 81 and a focal lengthchange by means of the zoom system 83.

In some examples, the ophthalmic device 1 comprises a compensationsystem 7 comprising movable masses 70 for compensating for accelerationforces caused by moved optical elements in order to avoid vibrations ofthe ophthalmic device 1 where possible or at least to reduce these. Thecompensation system 7 comprises one or more drives 71 coupled to themasses 70 and configured to move the masses 70 against the movements ofthe optical elements in accordance with the control by a control module.By way of example, the masses 70 are configured to compensateacceleration forces which are caused by the movements of opticalelements of the scanning device 2, for example by movements of themirror 20 and/or of the drives 21, 22, of the divergence modulator 81and/or of the zoom system 83.

It should be noted here that the control modules 23, 80, 82, which werelisted and described in the preceding paragraphs, each comprise acircuit, for example a (micro)processor, which is controlled by computercode of a program stored on a (non-transient) computer-readable medium,or another programmed logic unit or control electronics. The controlmodules 23, 80, 82 generate control signals, for example depending oncontrol programs and/or feedback signals of the scanning device 2, ofthe divergence modulator 81 or of the zoom system 83, for controllingthe scanning device 2, the drive system 200, the linear drives 21, 22,the divergence modulator 81, the zoom system 83, and/or the compensationsystem 7.

What is claimed is:
 1. An ophthalmic device for treating eye tissueusing laser pulses, comprising: a laser source configured to producelaser pulses; a projection optical unit comprising one or more lensesand configured for focused projection of the laser pulses to a focalpoint adjacent to an intended treatment area; a scanning device, with amovable mirror, arranged downstream from the projection optical unit,configured to deflect the laser pulses projected by the projectionoptical unit in at least one deflection direction and producing an imagefield curvature; and an optical correction lens arranged downstream ofthe projection optical unit and downstream of the scanning device,wherein the optical correction lens is configured to image, in a focusedmanner, the laser pulses deflected by the scanning device on theintended treatment area in the eye tissue, such as to correct the imagefield curvature produced by the scanning device.
 2. The ophthalmicdevice according to claim 1, wherein the scanning device is configuredto move the mirror about a pivot point lying on an optical axis of theprojection optical unit and on a surface of the movable mirror.
 3. Theophthalmic device according to claim 1, wherein the scanning devicecomprises a plurality of linear drives coupled to the movable mirror andthe ophthalmic device comprises a control module configured to controlthe linear drives in such a way that the linear drives rotate themovable mirror about a pivot point lying on an optical axis of theprojection optical unit and on a surface of the movable mirror.
 4. Theophthalmic device according to claim 1, wherein the optical correctionlens is configured to image, in the focused manner, the laser pulsesdeflected by the scanning device on the intended treatment area awayfrom a focal length of the projection optical unit.
 5. The ophthalmicdevice according to claim 1, wherein the optical correction lens isconfigured to produce a defined displacement or enlargement of a focallength of the projection optical unit.
 6. The ophthalmic deviceaccording to claim 1, wherein the optical correction lens is configuredto image, in the focused manner, the laser pulses deflected by thescanning device onto a focus with a reduced spot size.
 7. The ophthalmicdevice according to claim 1, wherein a combination of the projectionoptical unit and the optical correction lens is configured to produce adefined spot quality of the projected laser pulses, the defined spotquality of the projected laser pulses comprising at least one of: sizeof the spot, shape of the spot, diameter of the spot across a projectiondirection, and length of the spot in the projection direction.
 8. Theophthalmic device according to claim 1, further comprising a patientinterface device which can be fastened to the eye tissue of a patientand which is rotatably mounted about a pivot point of the movablemirror.
 9. The ophthalmic device according to claim 8, wherein theoptical correction lens is securely or detachably connected to thepatient interface device.
 10. The ophthalmic device according to claim8, wherein the patient interface device has a cavity provided forholding liquid, and an opening, which opening is closed by the eyetissue in a state of the patient interface device in which it isfastened to the eye tissue.
 11. The ophthalmic device according to claim1, wherein the scanning device is embodied such that the scanning devicecan be moved out of a beam path between the scanning device and the eyetissue in a state of a patient interface device in which the patientinterface device is fastened to the eye tissue.
 12. The ophthalmicdevice according to claim 1, further comprising a detection moduleconfigured to detect the optical correction lens and control a settingof the scanning device depending on a detection of the opticalcorrection lens.
 13. The ophthalmic device according to claim 1, furthercomprising a divergence modulator arranged upstream of the projectionoptical unit, wherein the divergence modulator is configured to shiftdivergence of a laser beam defined by the laser pulses based ondeflection of the laser pulses such that the image field curvatureproduced by the scanning device is at least partly compensated.
 14. Theophthalmic device according to claim 13, wherein the divergencemodulator comprises at least one of: two optical lenses arranged inseries, at least one of the two optical lenses being coupled to amovement driver in a manner displaceable on an optical axis formodulating the divergence of the laser beam; a deformable lens; adeformable mirror element; a spatial light modulator for modulatingwavefront of the laser beam; an area light modulator for modulatingreflection angles at a plurality of points of a reflection surface; arefraction modulator for modulating a refractive index of an opticalelement at a plurality of points in a cross section of a beam path; oran amplitude modulator for modulating an amplitude at a plurality ofpoints in the cross section of the beam path of the laser beam.
 15. Theophthalmic device according to claim 1, wherein the optical correctionlens is configured to image, in the focused manner, the laser pulsesdeflected by the scanning device for correcting the image fieldcurvature produced by the scanning device on a plane.
 16. The ophthalmicdevice according to claim 1, wherein the optical correction lens has afirst lens surface facing the movable mirror and a second lens surfacefacing the intended treatment area when treating the eye tissue.
 17. Theophthalmic device according to claim 16, wherein the first lens surfaceof the optical correction lens is equidistant to the pivot point of themirror.
 18. An ophthalmic device for treating eye tissue using laserpulses, comprising: a laser source configured to produce laser pulses; aprojection optical unit comprising one or more lenses and configured forfocused projection of the laser pulses to a focal point adjacent to anintended treatment area; a scanning device, with a movable mirror,arranged downstream from the projection optical unit, configured todeflect the laser pulses projected by the projection optical unit in atleast one deflection direction and producing an image field curvaturewhich causes the laser pulses projected by the projection optical unitto be deflected onto a curved treatment surface away from the intendedtreatment area; and an optical correction lens arranged downstream ofthe projection optical unit and downstream of the scanning device,wherein the optical correction lens is configured to image, in a focusedmanner, the laser pulses deflected by the scanning device on theintended treatment area in the eye tissue, such as to correct the imagefield curvature produced by the scanning device.
 19. The ophthalmicdevice according to claim 18, wherein the scanning device is configuredto move the mirror about a pivot point lying on an optical axis of theprojection optical unit and on a surface of the movable mirror.
 20. Adevice comprising: a laser source configured to produce laser pulses; aprojection optical unit comprising one or more lenses and configured forfocused projection of the laser pulses to a focal point adjacent to anintended treatment area; a scanning device, with a movable mirror,arranged downstream from the projection optical unit, configured todeflect the laser pulses projected by the projection optical unit in atleast one deflection direction and producing an image field curvature,wherein the scanning device is configured to move the mirror about apivot point lying on an optical axis of the projection optical unit andon a surface of the movable mirror, wherein the scanning devicecomprises a plurality of linear drives coupled to the movable mirror andthe ophthalmic device comprises a control module configured to controlthe linear drives in such a way that the linear drives rotate themovable mirror about a pivot point lying on an optical axis of theprojection optical unit and on a surface of the movable mirror; anoptical correction lens arranged downstream of the projection opticalunit and downstream of the scanning device, wherein the opticalcorrection lens is configured to image, in a focused manner, the laserpulses deflected by the scanning device on the intended treatment areain the eye tissue, such as to correct the image field curvature producedby the scanning device, wherein the optical correction lens isconfigured to image, in the focused manner, the laser pulses deflectedby the scanning device on the intended treatment area away from a focallength of the projection optical unit; a patient interface device whichcan be fastened to the eye tissue of a patient and which is rotatablymounted about a pivot point of the movable mirror, wherein the patientinterface device has a cavity provided for holding liquid, and anopening, which opening is closed by the eye tissue in a state of thepatient interface device in which it is fastened to the eye tissue; adetection module configured to detect the optical correction lens andcontrol a setting of the scanning device depending on a detection of theoptical correction lens; and a divergence modulator arranged upstream ofthe projection optical unit, wherein the divergence modulator isconfigured to shift divergence of a laser beam defined by the laserpulses based on deflection of the laser pulses such that the image fieldcurvature produced by the scanning device is at least partlycompensated, wherein the optical correction lens is securely ordetachably connected to the patient interface device.